Electrode assembly and method for signaling a monitor

ABSTRACT

An electrode assembly adapted to be attached to the skin over selected facial muscle groups picks up signals to be analyzed by an anesthesia adequacy monitor that measures the level of awareness of a living animal, typically a human being. The electrode assembly also includes a stimulator that stimulates a facial nerve to determine the level of paralysis, or neuro muscular block, of the facial muscles. Also disclosed is a method of manufacturing the electrode assembly by printing a pattern of electrically conductive material through a silk-screen or an ink type process onto a flexible layer, and then coating the result with a non-conducting adhesive except at points corresponding to sensing points for the desired muscle groups. Finally, a method for using such sensing and stimulating devices is shown in determining and maintaining an appropriate level of patient awareness, muscle paralysis, and analgesia under anesthesia.

[0001] This application is a continuation-in-part of U.S. patentapplication Ser. No. 08/475,024, filed Jun. 6, 1995.

FIELD OF THE INVENTION

[0002] The following invention relates to devices which are used in thefield of assessment of consciousness of a person, electromyography, andspecifically for measuring the clinical condition of a patient underanesthesia by noting the muscular activity related to facialmicro-expressions. This invention is also concerned with a method fordetermining the adequacy of anesthesia, and the level of paralysistherefrom, during surgery and otherwise through stimulating andmeasuring the muscular activity of the face. This method and this deviceallows for quick application of stimulating and multiple sensing meansfor the different muscles in the face.

INCORPORATION OF SPECIFICATION BY REFERENCE

[0003] U.S. Pat. No. 5,195,531 describing an anesthesia adequacy monitorand method, was issued to Henry L. Bennett on Mar. 23, 1993. Thedisclosure of U.S. Pat. No. 5,195,531 (the “First Bennett Patent”) isspecifically incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0004] In the past, when the face was stimulated and monitored forfacial expressions to indicate the depth of anesthesia, individualelectrodes were often applied one at a time. The time required to applyindividual electrodes was significant, especially when a full surgicaloperating crew was standing by or there were patients waiting for theirturn in the surgery operating theater.

[0005] Additionally, when individual electrodes are used, there was theproblem of multiple wires leading from the patient to any type of signalreceiving device. It was, of course, important to keep track of whichwire was connected to which electrode and where that electrode wasplaced on the face or other part of the patient's body. It was alsoimportant that the wires be hooked into the proper receptacle in anytype of monitor. Again, valuable time was taken up in order to assurethat the wires and electrodes had been properly placed on the patientand into the monitoring device.

[0006] In addition, as noted in the Background Of The Invention of theFirst Bennett Patent, there has been no adequate much less quicklyimplemented, method of monitoring the depth of unconsciousness of apatient under anesthesia. In this regard, anesthesia often seeks toprovide a variety of results for the patient during surgery and invasivemedical procedures. One such result is to provide oblivion through astate of unconsciousness. Another is to provide freedom from painregistration, conscious or unconscious. In seeking to achieve oblivionfor the patient, however, the anesthesia can and often does paralyzemuscle groups in varying degrees from partial paralysis to totalparalysis.

[0007] In addition to the issues explained about the prior devices andmethods explained in the First Bennett Patent, the surfaceelectromyogram devices identified therein did not sense a sufficientnumber of facial muscle groups to procure sufficient response data.Similarly, they also have not provided a mechanism to readily assess thelevel of paralysis (neuro muscular blockade) of facial muscle groupsbrought about by anesthesia and to then quickly process this type ofinformation in order to yield more accurate indicators of the depth ofparalysis of the person, if any, and also of the depth ofunconsciousness of a person in view of paralysis, if any.

[0008] As also shown in the prior art cited in the First Bennett Patentand in this specification, there are many electromyogram devices in theprior art for monitoring neuro muscular blockade during anesthesia(“NMBMs”). Another example of an NMBM is the Datex-EngstromNeuroMuscular Transmission Module, M-NMT. This NMBM utilizes twostimulator electrodes secured to a patient's wrist, a return electrodesecured to the patient's finger, and a sensor mounted on the patient'sthumb to monitor the hypothenar muscle stimulated by the ulnar nerve.This NMBM is not designed for easily and reliably mounting on andsensing facial muscle groups and does not include any means of receivingoutput from the sensors, calculating and reporting consciousnessindicators based on the output from the sensors, and also quickly andautomatically processing neuro muscular blockade information to moreaccurately and automatically measure the depth of paralysis, if any, andthe depth of consciousness of a person.

[0009] The following disclosures reflect the state of the art of whichapplicant is aware and is included herewith to discharge applicant'sacknowledged duty to disclose relevant information available. It isstipulated, however, that none of these references teach singly norrender obvious when considered in any conceivable combination the nexusof the instant invention as disclosed in greater detail hereinafter andas particularly claimed. PATENT NO. ISSUE DATE INVENTOR 2,902,030September 1, 1959 Kennedy et al. 3,572,322 March 23, 1971 Wade 3,774,593November 27, 1973 Hakata et al. 3,946,723 March 30, 1976 Servos4,082,087 April 4, 1978 Howson 4,353,372 October 12, 1982 Ayer 4,448,203May 15, 1984 Williamson et al. 4,583,549 April 22, 1986 Manoli 4,763,660August 16, 1988 Kroll, et al. 5,195,531 March 23, 1993 Bennett

FOREIGN PATENT DOCUMENTS

[0010] GB2, 113,846 Aug. 10, 1983 Rantala, B., et al.

OTHER PRIOR ART Including Author. Title, Date, Pertinent Pages, Etc.

[0011] Ritchie, G., et al., A Microcomputer Based Controller forNeuromuscular Block During Surgery, Annals of Biomed. Eng. 13:3-15(1985)

[0012] Edmonds, H. L., et al., Ouantitative Surface Electromyography inAnesthesia and Critical Care, Int J. Clin. Monitoring and Computing3:135-145 (1986)

[0013] Chang, T., et al., Continuous Electromyography for MonitoringDepth of Anesthesia, Anesth Analg. 67:521-5 (1988)

[0014] Edmonds, H. L., et al., Objective Assessment of Opioid Action byFacial Muscle Surface Electromyography (SEMG). Prog.Neuro-Psychopharmacol. & Biol. Psychiat. 12:727-738 (1988)

[0015] Paloheimo, et al.: Comparison of Upper Facial and HypothenarBlock, J. of Clinical Monitoring 4:256-260 (1988)

[0016] Tammisto, T., et al., Assessment of Neuromuscular Block:Comparison of Three Clinical Methods and Evoked Electromyography. Eur.J. Anaesthesiol. 5:1-8 (1988)

[0017] Nielsen, T. A., et al., Effects of Dream Reflection on WakingAffect: Awareness of Feelings, Rorschach Movement, and Facial EMG. Sleep12 (3):277-286 (1989)

[0018] Paloheimo, M., Assessment of Anaesthetic Adequacy with UpperFacial and Abdominal Wall EMG. Eur. J. Anaesthiol. 6:111-119 (1989)

[0019] Schwilden, H., Surveillance et Conduite de l'Anesthesie a l'Aidede l'EEG. des Potentiels Evoques. de l'EMG du Muscle Frontal ou duMonitorage de la Contractilite Oesophagienne Ann. Fr. Anesth. Reanim.8:162-166 (1989) McAdams, E. T., et al., Designing Biosignal MonitoringSensors. Sensors, :25-27 (1994)

[0020] Datex-Engstrom, NeuroMuscular Transmission Module ProductDescription, Internet Web Page (1998) (reporting prior art NMBM deviceby Datex-Engstrom discussed above)

[0021] The Kennedy et al. patent, U.S. Pat. No. 2, 902,030, describedthe electrodes at the bottom of column 3 as “small discs of spongerubber wetted with saline solution or small metal disc attached to thesurface of skin with adhesive tape.” A good contact was provided byapplication of a small amount of “electrode jelly” between the skin anda metal electrode. The electrodes were applied in the supra orbitalregion of the head of a person. No specific facial muscle group wasmentioned.

[0022] The Servos patent, U.S. Pat. No. 3,946,723, disclosed attaching apair of electrodes to opposite temples of a patient for detectinghorizontal eyeball movements using the cornea-retina potential. A secondpair of electrodes attached to brow and cheek bones detected, at adifferent time, the cornea-retina potential showing vertical eyemovement. Finally, a ground electrode was attached elsewhere on theface. The data gained was used to diagnose the presence of nystagmus asan indicator of vestibular disorders. A patient under anesthesia may nothave had reliable eye movements or even any purposeful eye movements atall.

[0023] The patent Williamson, et al., U.S. Pat. No. 4,448,203 taught theuse of a device for sensing electrical activity within target musclessuch as the masticatory muscle. One part of the device shown was a padwith two electrodes disposed on one side and a grounding electrodedisposed on the other side. The method of use for this device was forthe patient to hold the electrode pad up against his face with the twoelectrodes sides contacting the face and the one electrode sidecontacting the finger of the holder. Because the patient must hold theelectrode device against his face, this device was impractical for apatient under anesthesia.

[0024] The patent to Manoli, U.S. Pat. No. 4,583,549, disclosed a padwith either three or six electrodes placed in a fixed precordialconfiguration to assist in obtaining an ECG displaying electricalactivity of the cardiac musculature. The electrodes used were eithersilver plated copper discs with silver/silver chloride eyelets attachedto provide a convenient hook-up point for ECG recording cables, orcopper discs and copper connecting paths to connector edge tab which areetched on the flexible printed circuit board (with conductive gel coatedon the discs and the rest of the board coated with a non conductiveadhesive and release paper). Problems remained with the manufacture ofthe second described electrodes because of the care necessary to assurethat the conducting gel coated only the discs, that the insulating coatnecessary to avoid contact between the circuits and the patient's skinwas completely protective, and the necessity of hooking the sixconductor cable to the connector edge tab.

[0025] The patent to Rantala taught the use of a device for measuringthe depth of anesthesia which combined a surface electromyogram attachedto a facial muscle with an electroencephalogram and an electromyogramattached to a patient's hand. While this application did sense thefacial muscle activity, it interpreted the activity directly rather thanusing surface electromyogram readings to determine a facial expressioncorresponding to the consciousness of the patient, as does theapplicant's device. Furthermore, the applicant's device uses an array ofsurface electromyograms providing a more accurate representation of apatient's facial expression, and hence a more accurate representation ofthe patient's awareness level.

[0026] The article by Ritchlie, et al. in the Annals of BiomedicalEngineering, 1985 described the placement of stimulating and recordingelectrodes on the wrist and palm of the patient. The electrodes weredescribed as 30-gauge needles that were subcutaneously inserted near theulnar nerve. The recording electrodes were infant EKG surfaceelectrodes.

[0027] The article by Edmonds, et al. published in 1986 in theInternational Journal of Clinical Monitoring and Computing describedattaching adhesive skin electrodes over the belly of the frontalismuscle and also electrodes over the temporal bone and mastoid process.This was done for the purpose of determining the level of a patient'sawareness. In a later article by Edmonds, e al. in 1988 in the Prog.Neuro-Psychopharmacol. & Biol. Psychiat. an electrode was placed overthe same belly of the medial frontalis muscle with a reference electrodeplaced over the mastoid process. Again, no more than one muscle groupappears to have been attached to one individual electrode.

[0028] The article by Chang is of interest in that it also used asurface electromyogram attached to a facial muscle group andelectroencephalogram data during surgery. However, the method taught inthis article was designed to effectively administer anesthesia andprovided no method for monitoring the awareness level of the patient forpatient comfort as does the instant invention.

[0029] The article by Nielsen disclosed using electrode pairs with aninterelectrode distance of 2 cm. center to center. Facial sites selectedfor evaluating REM sleep were right and left corrugator supercilli (forsadness brow-knitting motion) and right and left zygomaticus major (forhappiness smiling). The readings were used to judge feeling-specificmotor activity during imagery reflection of REM sleep, not awarenessduring anesthesia.

[0030] The article by Paloheimo in the 1988 Eur. J. Anaesthiol, told ofusing surface electrodes in pairs to record facial electromyographicactivity. The first pair was attached on the forehead 3 cm above themid-eyebrow and on the mastoid process, with a ground electrode on thetemporal area. A second pair was located on the mamillary end anterioraxillary lines 10 cm. apart within the left dermatomes, with a groundelectrode on the external iliac process. No assembly of electrodes tosave applying electrodes one at a time was discussed.

[0031] The second article by Paloheimo in the J. of Clinical Monitoringdescribed attaching one pair of recording electrodes in the midline ofthe forehead and above the mid portion of an eyebrow for recordingelectrically evoked muscle potentials. Stimulation was provided byattaching a different pair of stimulating electrodes, one just posteriorto the lower part of the pinna and the other just anterior to thetragus. The facial muscle stimulated were procerus, frontalis,corrugator, and orbicularis oculi muscles. No mention was made ofrecording the patient's unstimulated state.

[0032] The article by McAdams, et al. published in 1994 discussed howflexible substrates have been printed with thin layers of silver loadedink to serve as electrodes. Also discussed was how a tab of a conductivesensor extended beyond the portion of an electrode coated with a solid,conductive adhesive hydrogel and was adapted to be connected to amonitor cable with an alligator clip. However an assembly having morethan one electrode was not discussed.

[0033] The device and method of this application more effectivelyachieves the purpose of providing for quick and sure attachment ofelectrodes to the tissue of a living animal, especially the face of ahuman patient undergoing surgery. The electrode assembly can, whenserving as the sensing means for picking up signals through the skin offacial muscle groups, provide an anesthesiologist with a reliableindicator of the patient's awareness level when the patient is otherwiseuncommunicative. One particularly preferred embodiment of the assemblyhas sensors for picking up signals of five different facial muscles andfurther includes NMBM stimulators and sensors to reliably and moreeasily monitor neuro muscular blockage (paralysis) of the patient.

[0034] The device and method of this application also more easily,readily, economically, and effectively senses one or more facial musclegroups, assesses the level of paralysis of facial muscle groups,processes the paralysis information in order to promptly indicate theparalysis level and the depth of unconsciousness of a person in view ofparalysis, if any.

SUMMARY OF THE INVENTION

[0035] The applicant's preferred device provides a convenient,effective, and economical electrode assembly for monitoring differentialelectrical states in various parts of a living animal. Preferably, theelectrode assembly can be used for simultaneous monitoring of the nervesignals to facial muscle groups to reflect the patient's facial muscletonus, which can be used as a reliable indicator of the level ofawareness for the patient while under anesthesia. In one embodiment, theelectrode assembly, especially when it includes at least threeelectrodes, preferably five electrodes, can be used to monitor thedifference between two muscle groups. In yet another embodiment, theelectrode assembly includes thirteen electrodes to monitor five musclegroups and stimulate, and monitor the resulting effect on, at least oneof the muscle groups.

[0036] The preferred electrode assembly has a pattern of electricallyconductive material printed on a flexible layer, and also anon-conductive adhesive, which serves to isolate electrodes from eachother. The assembly is adapted to follow the facial contours of apatient. Also the electrode assembly, by having a substantially uniformthickness, prevents pressure points from developing when the electrodeassembly comes between the living animal tissue and any support surfacesuch as an operating table or bed pillow.

[0037] Using the electrode assembly as a sensing means for judging thestate of patient awareness, an anesthesiologist can better control andprovide greater comfort for a patient undergoing anesthesia during thecourse of surgery. Specifically, the electrode assembly allows quick andsure attachment and a preconfigured pattern for applying the electrodesover selected facial muscle groups. The design of the electrode, withthe trailing ribbon attached to the electrode sensing points in anunbroken electrical pathway, allows a monitor or other signal processingdevice to receive what the electrodes have picked up. After processingthe signals using one or more algorithms, the anesthesiologist may viewa display representing the patient's face or other indicators derivedfrom the processed signals. Based upon this information, theanesthesiologist then can control the dosage of anesthetic to reach thedesired level of patient awareness, paralysis, and analgesia. These areall done independently with different drugs based on the three signalsfrom FACE-level of a) awareness, b) paralysis, and c) analgesia.Additionally, the signal processor can be informed of artifactgenerating events which can be subtracted out from the signal receivedby the processor or monitor. This allows the surgeon to use such devicesas an electric cauterizer during the course of surgery withoutinterfering with the anesthesiologist efforts to maintain a desiredlevel of patient awareness.

[0038] Fabrication of the electrode assembly can be based upon asilk-screen printing method, but preferably an ink type printing processis used. A flexible layer, which is characterized by resisting lineardistortion, is printed with a pattern of electrically conductivematerial. Over this pattern is placed non-conductive adhesive either inthe form of a pre-shaped pad with apertures allowing for contact withthe living tissue of the animal through an electrolytic medium, or thepattern of electrically conductive material is coated with anon-conductive adhesive except at points where pads prevent coating andsuch points correspond to sensing points on the animal. A detachablelayer over the electrode area can preserve the electrode assembly duringshipping.

[0039] In designing the preferred pattern of electrically conductivematerials, the locations of the Corrugator and Frontalis muscle groupscan be taken into consideration for one set of electrodes andstimulators, as well as the Zygomatic, Orbicularis Oculi, and Masseterfacial muscle groups in the case of a second group of electrodes.Finally the ribbon trailing off the area of contact between theelectrodes and tissue can be adapted at the opposite end to be engagedby the prongs of a spring-biased signal input clamp, or preferably amechanical clamping ZIF connector.

[0040] The electrode assembly can thus be attached to a processor toprocess output from the sensing electrodes according to predeterminedanalysis programs or algorithms. The processor can be attached to adisplay or other device reporting or utilizing output from the processorin order to monitor the consciousness, paralysis, or analgesia of theperson to whom the electrode assembly is attached.

[0041] Preferably, the electrode assembly includes stimulators forstimulating the upper branch of the facial nerve and recording theresponse at the Corrugator facial muscle preferably through the use ofnon-invasive, interferential stimulation. Upon stimulation, the sensorsat the Corrugator facial muscle area indicate the response of thatmuscle area and thus provide an indication of the level of paralysis, ifany (including undesirable total paralysis rendering the facial musclesincapable of micro-movements and the attendant indications awareness orstress information). Partial paralysis information can be used by theprocessor to adjust paralysis-affected monitoring of the facial musclesensors, such as monitoring pursuant to sensor summation algorithms toreport the awareness of the monitored person. As long as the paralysisis not total, the processor can also apply, and report the outcome of,other methods of analysis, such as sensor differential or ratioalgorithms that report the stress or pain registering with the personbeing monitored.

[0042] There are other aspects of the invention that will becomeapparent as the specification proceeds below.

OBJECTS OF THE INVENTION

[0043] Accordingly, it is an object of the present invention to providea device which allows for quick and accurate placement of electrodesupon the tissue of a living animal to monitor differential electricalstates.

[0044] Another object of the present invention is to provide anelectrode assembly which is easily and economically manufactured bywell-known techniques such as silk-screen or ink type printing process.

[0045] Another object of the present invention is to provide a sensingmeans preconfigured to pick up signals from certain facial muscle groupsthat will serve as a reliable indicator of the level of awareness of apatient undergoing anesthesia wherein the same preconfigurationarrangement of electrodes can be used with different individuals.

[0046] A further object is to provide stimulators, preferably of thenon-invasive type and mounted within the electrode assembly, forstimulation of a facial nerve and measurement of the responsivemovement, if any, of the stimulated facial muscle.

[0047] A related object is to have the stimulating and sensing meanssense the level of paralysis, of any, of the facial muscles.

[0048] Yet another object of the present invention is to provide for anelectrode assembly of substantially uniform thickness which assures thatwhen the assembly is in between the patient's tissue and a bed pillow ormattress or surgery table that no pressure points are developed duringthe monitoring of the patient.

[0049] Another object of the present invention is to provide a methodfor informing an anesthesiologist of the level of patient awarenessthrough the use of an electrode assembly which picks up signals fromfacial muscle groups which can be processed to provide a displayrepresenting the patient's facial muscle tonus, the display can be usedby the anesthesiologist to monitor the patient's level of awareness andrespond thereto with differing dosages of anesthetic and/or level ofanalgesia.

[0050] Viewed from a first vantage point it is the object of the presentinvention to provide an electrode assembly for monitoring differentialelectrical states in various parts of a living animal, comprising: aflexible layer, a pattern of electrically conductive material, disposedupon one side of the flexible layer wherein the pattern contains atleast two electrodes and is adapted to be connected to a signalreceiving means, and a non-conducting adhesive that electricallyisolates at least one electrode from another electrode, but allows atleast two electrodes to contact the tissue of the living animal.

[0051] Viewed from a second vantage point it is the object of thepresent invention to provide a method for maintaining an appropriatelevel of patient awareness under anesthesia, the steps including:providing at least one electrode assembly, comprising a flexible layer,a pattern of electrically conductive material, disposed upon one side ofthe flexible layer wherein the pattern contains as at least twoelectrodes and is adapted to be connected to a signal receiving means, anon-conducting adhesive that electrically isolates at least oneelectrode from another electrode, but allows at least two electrodes tocontact the tissue of said patient; and attaching the assembly to theface of the patient, picking up a signal with the electrodes, receivingthe signal in a processing device through a signal receiving means,processing the signal received from the electrodes to determine whatfacial expression the signal represents by comparing the signals fromdifferent electrodes, the signals being reflective of the patient'sfacial muscle tonus, displaying the processed signal for viewing by ananesthesiologist on a display, anesthetizing the patient with an initialdosage of anesthetic to create muscle relaxation in a desired level ofawareness, and controlling the patient's level of awareness andanalgesia.

[0052] Viewed from a third vantage point it is the object of the presentinvention to provide a sensing means adapted to signal an awarenesslevel detector for informing an anesthesiologist of the level ofawareness of a patient under anesthesia through detection of thepatient's facial expression comprising, in combination: a flexiblelayer, a pattern of electrically conductive material, disposed upon oneside of the flexible layer wherein the pattern contains as at least twoelectrodes and is adapted to be connected to a signal receiving means, anon-conducting adhesive that electrically isolates at least oneelectrode from another electrode, but allows at least two electrodes tocontact the face of said patient.

[0053] Another object is to provide a device and method that stimulatesand senses micro-motion in facial muscles in order to: (i) determine andreport the level of paralysis of the muscles; (ii) adjust awarenessdetermining algorithms to continue to adequately report the awareness orconsciousness of a person despite partial paralysis; (iii) report thelevel of pain or stress registering with a person; and (iv) provideinformation about awareness, paralyzation, and stress or pain so thatanesthesia may be more appropriately administered to procure the desiredoutcome and minimization or elimination of pain, stress, andconsciousness of a patient during surgery, for example.

[0054] These and other objects of the present invention, such as thoseset forth in the First Bennett Patent, will be made manifest whenconsidering the following detailed specification when taken inconjunction with the appended drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0055]FIG. 1 is a perspective drawing of a two-muscle-area electrodeassembly as engaged with a spring biased signal receiving clamp.

[0056]FIG. 2 is a perspective drawing showing the two-muscle electrodeassembly being engaged by the spring biased signal receiving clamp.

[0057]FIG. 3 is a representation of the first step fabricating thetwo-muscle electrode assembly wherein electrically conductive materialis applied to the flexible layer.

[0058]FIG. 4 is the second step in the fabrication of the two-muscleelectrode assembly wherein non-conductive adhesive is applied to theresult of the fabrication step shown in FIG. 2.

[0059]FIG. 5 is a perspective view of an alternate second step wherein apre-formed shape of non-conductive adhesive is about to be mated withthe result of the fabrication step shown in FIG. 2.

[0060]FIG. 6 is a perspective view of the third step in the fabricationprocess wherein a detachable pad is applied to the result of the secondstep of the fabrication process.

[0061]FIG. 7 is a cross section view of the two-muscle electrodeassembly taken along line 7-7 of FIG. 1.

[0062]FIG. 8 is a perspective view of the two-muscle electrode assemblybeing applied to the person's face after application of an electrolyticmedium to the electrode contact points.

[0063]FIG. 9 is a front plan view of two two-muscle electrode assemblydevices of this application in place on a person's face.

[0064]FIG. 10 is a block diagram representing the relationships of thesteps of method of this application for sensing four facial muscle areaswithout active stimulation by the electrode assembly.

[0065]FIG. 11 is a block diagram representing the fabrication stepsinvolved in manufacturing the electrode assembly devices of thisapplication.

[0066]FIG. 12 is a partial perspective view of an alternative unitaryelectrode assembly, applied to the person's face, having electrode's forsimultaneously sensing motion of five facial muscle areas as “Train ofFour” and tetanic constant current nerve stimulation. However, thisdevice may stimulate the nerve by interferential stimulation (i.e.,applying two higher frequencies in order to obtain a low differentialfrequency for stimulation of the nerve).

[0067]FIG. 13 is a block diagram representing the relationships of thepre-surgery steps of the alternative method of this specification forsensing five facial muscle areas and actively stimulating a muscle areawith the five-muscle electrode assembly.

[0068]FIG. 14 is a block diagram representing the relationships of thesteps of the alternative method of this specification for sensing fivefacial muscle areas and actively stimulating a muscle area with thefive-muscle electrode assembly during surgery.

[0069]FIG. 15 is a block diagram representing the general relationshipsof the elements of the alternative device and method of this applicationfor sensing five muscle areas and stimulating one muscle area.

[0070]FIG. 16 is a plan view of one possible output for display in thealternative device of this application for sensing five muscle areas andstimulating one muscle area.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0071] Considering the drawings, wherein like reference numerals denotelike parts throughout the various drawing figures, reference numeral 10is directed to a two-muscle electrode assembly according to the presentinvention. Referring now to FIG. 1, an electrode assembly 10 is shownengaged with spring biased signal input clamp 18. Leading from electrodecontact points 12 are electrical connecting paths 14 which carry anysignal received by electrode contact points 12 to spring biased signalinput clamp 18. The electrode contacts points 12 and electricalconnecting paths 14 are disposed upon flexible layer 24. Flexible layer24 can be made from any of a number of flexible plastic substrates.Depending on the type of plastic used, the thickness of the flexiblelayer can vary from 1 mil to 3 mil, preferably being 2 mil for preferredplastic. A preferred embodiment of electrode assembly 10 uses one typeof plastic that is a combination of vinyl and mylar plastics. Going onnow to FIG. 2, spring bias signal input clamp 18 is shown with the jawsopen ready to receive electrode assembly 10. The ribbon of the electrodeis guided into the proper position in the jaws of the clamp 18 by guides19. Contact points 20 engage individually, each one of the electricalconnecting paths 14 because the electrical connecting paths 14 have beenspaced apart a proper distance to ensure engagement with only onecontact point 20 of spring biased signal input clamp 18. FIG. 1 does notshow the electrode assembly in a perspective view of actual use, it isfor illustration purposes alone. It is contemplated that the electrodeassembly 10 would first be placed upon the living animal tissue, such asa patient's face, before being hooked up to spring biased or ZIF typesignal input clamp 18. Of course, it is to be understood that othermethods of engagement for electrode assembly 10 could be used to carrythe signal picked up by electrode assembly 10 and deliver it to a signalprocessor.

[0072] Referring now to FIG. 3, the flexible layer 24 is shown as beingprepared to receive the electrically conductive material 16 that makesup electrical connecting paths 14 and electrode contact points 12.Electrically conductive material 16 is carried to mask means 22 bysqueegee 26. Mask means 22 can be a silk-screen used in a silk-screenprinting process or an ink type process. As shown, mask means 22contains openings 28 that allows electrically conductive material 16 insqueegee 26 to flow through onto flexible layer 24 when mask means 22 islowered into contact with flexible layer 24.

[0073] After allowing the electrically conductive material to dry, theflexible layer 24, with a pattern of electrically conductive material 16displayed thereon one side, can be treated in various ways to completethe fabrication of electrode assembly 10. As shown in FIG. 4, buttons 30are placed over the electrode contact points 12. Then, non-conductiveadhesive 32 is sprayed onto a side of the flexible layer 24 with thepattern of electrically conductive material 16. These buttons 30 areshown as being put into engagement with the electrode contact points 12.The electrode contact points 12 will match up with later locations onthe skin of the animal. Typically the locations are placed so that theelectrode contact points 12 can pick up signals from the desired musclegroups. Non-conductive material 32 is now applied by spray gun 34 tocoat the entire surface of flexible layer 24 including electricallyconductive material 16 and buttons 30. After the material has beensprayed on, the buttons 30 do not adhere to the electrode contact points12. This allows easy removal of any non-conductive material from thearea over the electrode contact points 12, especially if anon-conductive material 32 has been scored over the perimeter ofelectrode contact points 12.

[0074] Other methods of applying non-conductive material 32 can includea second silk-screen printing similar to FIG. 3. The non-conductivematerial 32 is preferably applied using a printing roller without anymask means, as long as buttons 30 are used. However the non-conductivematerial 32 is applied to flexible layer 24, it is necessary to ensurethat the electrically connecting paths 14 and electrode contact points12 do not come into contact with each other. If allowed to, this couldwell short out the pathway for delivering the signal received to theprocessor unit.

[0075] Another way to apply the non-conductive material 32 to flexiblelayer 24 with electrically conductive material disposed on one side isfor a pre-formed shape, like a pad, to be placed over the flexible layer24 with electrically conductive material 16 on one side as shown in FIG.5. Within this pre-formed layer, at the appropriate spots over theelectrode contact points 12, are apertures 38, preferably filled with anelectrolytic medium 40 seen later in FIG. 7 such as lanolin based creamcontaining electrolytes (such as Signa Creme 1705 available from ParkerLaboratories). When applied to the tissue of a living animal, theapertures allow signals to be received by electrode contact points 12,especially if an electrolytic medium is used. Because the layer ispre-formed, mating it with the pattern of electrode contact points 12 onflexible layer 24 should not require much micro-adjustment of thelocation.

[0076] Referring now to FIG. 6, flexible layer 24 with electricalconnecting paths 14 and electrode contact points 12 and non-conductivematerial 32 applied is ready for mating with detachable pads 42. As canalso be seen in FIG. 6, electrode assemblies 10 are often produced inmultiple numbers on a single flexible sheet 24. After detachable pads 42are mated with the electrode assemblies 10, the assemblies 10 can beseparated. Separation can be done through use of a knife, scissors, orother appropriate cutting means. As can be observed in FIG. 6, theelectrode assemblies are sometimes mirror images of each other. Also,depending upon the muscle groups that the user may wish to monitor,electrode assemblies 10 can assume different configurations for theirelectrode contact points. Although FIGS. 3, 4 and 5 show only thepreparation of a single electrode assembly, the silk-screen mask 22 canhave many electrode assembly patterns present and a number of electrodeassemblies 10 can be printed onto a flexible layer 24.

[0077] Referring now to FIG. 7, the electrode assembly 10 is seen incross section. Flexible layer 24 accounts for much of the thickness ofthe assembly 10. Differing electrical connecting paths 14 and theelectrode contact points 12 are also present. The space above contactpoints 12 is vacant, while non-conductive adhesive 32 is above otherparts of flexible layer 24. At the far right, the space above contactpoint 12 is pre-filled with electrolytic medium 40. However, thesubstantially uniform thickness of electrode assembly 10 is preserveddue to the thinness of the non-conductive adhesive 32. Thus, thepresence or absence of non-conductive adhesive 32 does not radicallychange the thickness of electrode assembly 10. Therefore, when electrodeassembly 10 is between the tissue of a living animal and a supportmeans, such as an operating tale a pillow on a bed, then substantiallyuniform thickness prevents any point from becoming a pressure point. Thelack or pressure points in electrode assembly 10 when so used preventsthe development of sores and other discomfort for the patient.

[0078] Referring now to FIG. 8, a patient's face is prepared to receiveelectrode assembly 10 which has no electrolytic medium packaged with it.It is preferred to use pre-jellied electrodes in large-scalemanufacturing. An electrolytic medium 40 such as Signa brand creme,could also be applied to the electrode assembly, if the assembly is notprovided with a medium already in contact wells over control points 12.This medium 40 comes in the form of a thick lotion. The medium ispreferably thick enough to hold a bead shape in the well of theelectrode contact point. Other electrode assemblies 10 can be suppliedwith the medium in the well, before the detachable pads 42 are mated tothe flexible layer 24. Other electrolytic mediums 40 such as electrodepaste with adhesive characteristics can be applied to the electrodeassembly 10. The skin over the orbicularis oculi 48 muscle group and thezygomatic 50 muscle groups in FIG. 8 is shown as ready to receive theelectrode assembly 10. FIG. 8 also shows electrode assembly 10 beingpositioned to be applied to the patient's face over the muscle groupswhose monitoring is desired. In a similar fashion, other muscle groupscan have electrolytic medium 40 put into the contact points wells, andthen electrode assemblies 10 applied.

[0079] Now referring to FIG. 9, two-muscle electrode assemblies 10 havebeen applied to different areas of a human face. The uppermost assembly10 is applied to the corrugator 44 facial muscle group and the frontalis46 facial muscle group. For the lower electrode assembly, theorbicularis oculi 48 facial muscle group is contacted by the upper halfof the electrode. The lower inner electrode contact points are over thezygomatic facial muscle group 50. Ground electrodes 52 are also presentin each electrode assembly 10 shown in FIG. 3.

[0080] After applying the electrode assembly 10 with the electrolyticmedium 40 in the electrode contact point wells, the heat of thepatient's skin causes some mediums, such as the aforementioned Signacreme to partially liquefy and flow into the patient's sweat glands.This flow establishes better electrical contact and hence the electrodeassembly 10 can better pick up the nerve impulses to the target musclegroups. If the electrotytic medium 40 does not liquefy, sometimes thepatient's sweat glands produce perspiration which establishes a betterelectrical pick-up of nerve signals.

[0081] Referring now to FIG. 10, in use and operation the awarenesslevel monitor receives signals from electrode assembly 10 placed uponthe face of the patient. The monitor may be used by an anesthesiologistor other qualified operator to maintain the appropriate level of patientawareness during surgery. Finally, the anesthesiologist confirms theelectrode assembly proper placement on the face of the patient. Baseline reading may be then established. The patient is then givenanesthesia appropriate for the circumstances. The anesthesiologist maythen monitor the display 54 to determine the patient's level ofawareness as reflected in changes in the muscle tonus. Once surgerybegins, the anesthesiologist may use the display 54 to monitor themagnitude of the patient's response to what otherwise would be anobjectively painful surgical stimulus. If the display 54 demonstrates anunacceptably high level of awareness and/or registration of pain, theanesthesiologist may administer more anesthesia or take other correctiveaction. If the display 54 demonstrates an unacceptably low level ofawareness, other corrective measures may be taken. In this way thepatient's comfort may be maximized and the patient's reaction to thesurgical procedure and therefore recovery time can be minimized.

[0082] Also necessary to have a accurate display 54 is the removal ofartifacts in the signal caused by such artifact generators as electriccauterizing devices. When this device is used, some electric currentflows through the patient causing an anomaly in the signals as read bythe electrode contact points 12. The artifact detector connected on oneend to the cauterizing device or other artifact generator and on theother end to a first signal conduit. When an artifact is detected by theartifact detector, the detector then filters out the portion of thefirst signal representing the artifact.

[0083] Referring now to FIG. 11, a block diagram showing themanufacturing method for providing an electrode assembly is displayed.The first step, as -previously shown in FIGS. 3, 4, 5, and 6, is toprovide a non-extensible material to serve as flexible layer 24. Thenext step is to apply electrically conductive material 16 through maskmeans 22 to flexible layer 24. After this is accomplished, the next stepis to coat with a non-conducting adhesive 32, preferably through a maskmeans. As has been previously discussed this is one method. Othermethods may include mating a pre-formed layer with the flexible layer 24with attached pattern of electrically connecting paths 14. The next stepis for a detachable pad 42 to be engaged with the now non-conductingadhesive coated flexible layer. Finally, if there are more than oneelectrode assemblies 10 on the flexible layer 24, the material must becut so that the individual assemblies 10 can be separated.

[0084] Referring now to FIG. 12, an alternative electrode assembly orsensor-stimulator array 100 is shown as applied to a patient's face F tosense five muscle groups and stimulate at least one of the themaccording to the alternative method of this specification. This unitaryand integrated sensor-stimulator array 100 is manufactured generallyusing the same techniques described above for the alternative two-muscleelectrode assembly 10. The sensor-stimulator array 100 is, however,easier to apply and maintain in place on the face F of the patient thanis the combination of two two-muscle electrode assemblies described inthe First Bennett patent.

[0085] The array 100 has a first sensor 102, a second sensor 104, athird sensor 106, a fourth sensor 108, a fifth sensor 110, a groundsensor 112, and a stimulator electrode 114. The first, second, third,fourth, and fifth sensors 102, 104, 106, 108, and 110 are mounted overthe Frontalis, Corrugator, Orbicularis Oculi, Zygomatic, and Massetermuscle groups, respectively. The first through fifth sensors 102, 104,106, 108, 110 each have two electrodes or electrode sensors, each suchpairing being denoted as + or − in the numbering for the particularelectrode pair (e.g., 102+and 102− as the pair for the first orFrontalis sensor 102).

[0086] The first through fifth sensors 102, 104, 106, 108, 110 andground sensor 112 are generally constructed as described the FirstBennett Patent. As a result, each sensor 102, 104, 106, 108, 110 andground sensor 112 collectively generate, as shown in FIG. 15, thecollective five-muscle signal or group of signals 115 of thisalternative monitoring device, generally 113, and method. Thefive-muscle signal 115 is then passed through a pre-amplifier 27 andprocessed in generally the same fashion as described in the FirstBennett Patent with the modifications and additions described herein.

[0087] Referring back to FIG. 12, the stimulator sensor 114 of thisalternative embodiment 100 utilizes stimulator electrodes or electrodesensors 114H and 114L to stimulate the upper branch of the facial nervefor recording at the Corrugator muscle in the patient's face F.(Alternatively, the stimulator sensor 114 could instead consist of amuscle sensor such as one of the first through fifth muscle sensors 102,104, 106, 108, 110.) By this device and method, the facial muscle nervelying under the surface of the skin can be activated without trauma tothe nerve or tissues of the patient. The stimulator sensor 114H, 114L isconnected to, as shown in FIG. 15, a stimulator activation device 116 ofthe type well known in the art. Upon temporary suspension of recordingof electromyograms by the monitoring device 113, the stimulatoractivation device 116 can be activated by an operator or anesthetist(not shown) to preferably carry to the patient's face F through thestimulator sensor 114 four equally spaced electrical pulses 50microseconds in duration each presented as a square wave at a frequencyof 2 Hz. Optionally, and referring to FIG. 12, the pulses on the firststimulator electrode 114H have a carrier frequency of 10,050 Hz, and thepulses on the second stimulator electrode 116L have a carrier frequencyof 10,000 Hz. In this embodiment, one of the two sensors serves as theelectrical return for the current. The two high difference frequenciesdelivered by stimulator sensors 114H, 114L stimulate the Corrugatornerve at the much lower interferential frequency generated between them,50 Hz. The high difference frequencies of the stimulator sensors 114H,114L penetrate biological tissues more effectively than lowerfrequencies but are not effective at stimulating muscles within thetissues. The resulting interferential low-frequency 10 Hz pulsesdelivered to the Corrugator nerve are highly effective at stimulatingnerves such as the Corrugator nerve deep under the skin of the patient'sface F.

[0088] Immediately after such stimulation, the second sensor 104 recordsa stimulation signal based on the level of resulting activity in theCorrugator muscle area in the face F. As shown in FIG. 15, thisstimulation signal is transmitted to the computer 60, which records thesignal, processes it according the algorithms loaded in the computer 60,and generates a display of the level of activity on the display 80.

[0089] Upon resumption of the recording of electromyograms by themonitoring device 113, the five-muscle activity signal 115 is againtransmitted to pre-amplifier 27, through the detector 40, and into thecomputer 60. The computer applies an “Aware” and a “Stress” algorithm tothe signal 115 and creates a second signal 120. This second signal orgroup of signals 120 represents, and causes the display 80 to show: (1)the facial expression of the patient P such as described in the FirstBennett Patent; and/or (2) as shown in FIG. 16, a graphicalrepresentation of the activity sensed for each of the five facial muscleareas and a “Stress” and “Aware” index.

[0090] The “Aware” algorithm for determining the “Aware Index” is asummation index using the following formula:

O+F+C+Z=“Aware Index”

[0091] Where:

[0092] O is the muscle tonus of Orbicularis Oculi muscle,

[0093] F is the muscle tonus of the Frontalis muscle,

[0094] C is the muscle tonus of the Corrugator muscle,

[0095] Z is the muscle tonus of the Zygomatic muscle, and

[0096] The “Stress” algorithm for determining the “Stress Index” is adifferential or ratio based index, preferably using the followingformula with the same nomenclature as set forth above:Stress  Algorithm   $\begin{matrix}{\left. a \right)\quad} & {{{{IF}\left\lbrack {O \geq Z} \right\rbrack}\quad {{or}\quad\left\lbrack {O < {Z\quad {and}\quad C} \leq F} \right\rbrack}},{then}} \\\quad & {{Stress} = {\left( \frac{\left( {C - F} \right) + \left( {O - Z} \right)}{C + F + O + Z} \right) \times 100}} \\\left. b \right) & {{{{IF}\left\lbrack {O < Z} \right\rbrack}\quad {{and}\quad\left\lbrack {C > F} \right\rbrack}},{then}} \\\quad & {{Stress} = {\left( \frac{\left( {C - F} \right) + \left( {M - Z} \right)}{C + F + M + Z} \right) \times 100}} \\\left. c \right) & {M\quad {is}\quad {displayed}\quad {separately}\quad {in}\quad {all}\quad {cases}\quad {as}\quad M}\end{matrix}\quad$

[0097] The Aware algorithm and resulting index provides a measure of thedegree of patient oblivion and unconsciousness. However, because thisalgorithm is a summation of muscle tonus values which will diminish dueto muscle paralysis brought about by anesthesia, the Aware Index shouldbe calibrated to adjust for the level of paralysis of the facialmuscles. This is accomplished by having determined an originalunparalyzed Corrugator stimulator signal, as described above, prior toadministration of anesthesia. Upon administration of anesthesia, asubsequent Corrugator stimulator signal is determined, again accordingto the method described above. The degree of paralysis of the facialmuscles is measured by the percentage change of the stimulator signalfrom the unparalyzed to the anesthetized state. Since muscle activity isinversely proportional to the degree of paralysis, the computer 60multiplies the Aware value calculated during stimulation underanesthesia, at that particular point in time, by the inverse of theremaining level of activity as compared to the original, unparalyzedstate, except in the event of total paralysis when the remainingactivity level is null. Thus, if the Aware value calculated bystimulation during anesthesia is 5% as great as that calculated beforeapplying anesthesia, the computer 60 multiplies the Aware value duringanesthesia at that point in time by a factor of 20 and displays theresulting Aware Index on the display 80. In the event that the remainingactivity level is null, the computer 60 generates an Aware Index ofzero.

[0098] This method of stimulation and comparison of muscle activity fromthe pre-anesthesia to the anesthetized state thus provides a monitor formore precise titration of anesthetic agents during administration ofanesthesia. In addition, in the event of total paralysis or neuromuscular block of the facial muscles, the Aware Index will be zero andthe resulting display of a zero value for the Aware Index on the display80. The anesthesiologist is thus alerted to the state of total paralysisof the facial muscles as well as the inability to rely on anymeasurement of muscle activity ill the face to indicate the patient'strue level of consciousness in view of the total paralysis of the facialmuscles.

[0099] Except in the case of total paralysis indicated by the zeroing ofthe Aware Index, the Stress algorithm provides a signal based on theoutput from the lower brain centers of the basal ganglia and limbicsystems directly to the patterning of facial muscles. These signals,known as facial expressions, are the result of the combination ofpatient arousal, pharmacological and anesthetic drug states, andsurgical stimulation. By providing a Stress Index based on thesesignals, the anesthesiologist is provided with an indicator of the truestate of analgesia and a significant tool for more precise titration ofanalgesic agents.

[0100] In use and operation, the consciousness or anesthesia adequacymonitor 10 may be used by an anesthesiologist or other operator tomonitor and/or maintain patient consciousness as desired duringadministration of anesthesia as suggested in FIGS. 13 and 14. Initially,the anesthesiologist configures the sensor array (100 in FIG. 12) on theface F of the patient P. Referring now to FIG. 14, the patient P is thegiven anesthesia appropriate for the circumstances. As shown in FIG. 13,a base line reading may then be established, including stimulation ofthe facial muscle to determine the response level of the facial musclesin the completely unparalyzed state. The anesthesiologist may thenmonitor the display 80, and as desired stimulate the patient's facialnerve, to determine the patient's level of paralysis and consciousnessas reflected by changes in muscle tonus reported on the display 80. Thedevice preferably includes an automatic mode to stimulate at regularintervals. Initial calibration in the anesthetized, but unparalyzedstate, then rapid repetitions for 5 minutes every 15 seconds, then onceever 4-5 seconds thereafter using the “train of four” method previouslydescribed. Once the surgery begins, the anesthesiologist may use thedisplay 80 to monitor the magnitude of the patient's response tosurgery, including my intermittent stimulation of the patient's facialnerve. If the display demonstrates an unacceptably high level of patientawareness, or total paralysis of the facial muscles, theanesthesiologist may take corrective action. In this way, the patient'scomfort can be maximized and the patient's reaction to surgery, andtherefore the patient's recovery time, can be minimized.

[0101] As also noted in the First Bennett Patent, the consciousnessmonitoring device 10 may also be used with a patient who has sufferedinjury and is experiencing a diminished level of consciousness. Thedevice 10, or portions thereof, may also be used in other settings inwhich consciousness monitoring is desired. The device may be used aswell in ICU for titrating sedation, analgesia and/or paralysis.

[0102] Moreover, having thus described the invention, it should beapparent that numerous structural modifications and adaptations may beresorted to without departing from the scope and fair meaning of theinstant invention as set forth hereinabove and as described hereinbelowby the claims.

We claim:
 1. An apparatus for indicating the consciousness of a person,comprising in combination: A. an array of facial muscle sensors adaptedto generate sensor signals representing the simultaneous activity of atleast four different facial muscle areas, each of which elicitdistinctive patterns of facial expressions of the person; and B. asensor signal processor operatively coupled to the sensors to receivethe sensor signals from the facial muscle sensors and, based on thesensor signals, automatically generate an output signal indicating theconsciousness of the person.
 2. The consciousness indicating apparatusof claim 1 wherein the facial muscle sensors are surface electromyogramsadapted to be physically attached the person's face in positionsallowing the monitoring of the different facial muscles.
 3. Theconsciousness indicating apparatus of claim 2 wherein said facial muscleareas are selected from among the frontalis area, the corrugator area,the zygomatic area, the masseter area, and the orbilaris oculi area. 4.The consciousness indicating apparatus of claim 2 also having: (i) afacial muscle stimulator adapted to activate a facial nerve in at leastone of said facial muscle areas, and (ii) a facial nerve processoradapted to receive sensor signals from the facial muscles sensors insaid nerve-activated facial muscle area, (b) determine a paralysis levelfor said nerve-activated facial muscle area, and (c) adjust the sensorsignal processor's generation of at least a portion of the output signalaccording to the determined paralysis level, whereby the output signalindicates the consciousness of the person despite partial paralysis ofthe nerve-activated facial muscle area.
 5. The consciousness indicatingapparatus of claim 4 wherein the facial muscle stimulator includes afirst facial muscle stimulator providing a first carrier signal at afirst predetermined frequency to one facial muscle area and a secondfacial muscle stimulator providing a second carrier signal at a secondpredetermined frequency to the one facial muscle area, whereby the firstand second facial muscle stimulators cooperatively stimulate a facialnerve in the one facial muscle area at a third stimulation frequencycomprising the difference between the first and second predeterminedfrequencies.
 6. The consciousness indicating apparatus of claim 5wherein said facial muscle areas are selected from among the frontalisarea, the corrugator area, the zygomatic area, the masseter area, andthe orbilaris oculi area.
 7. The consciousness indicating apparatusclaim 6 also having an artifact filter for filtering the sensor signalsreceived by the sensor signal processor to remove an artifactrepresenting muscle activity caused by known stimulus to the person notindicative of the person's consciousness, whereby the output signalgenerated by the sensor signal processor indicates the consciousness ofthe person without unwanted distortion from such artifact.
 8. Theconsciousness indicating apparatus of claim 7 wherein the artifactfilter includes an artifact detector connected to an external device toprovide a detection signal to the artifact filter upon activation of theexternal device.
 9. The consciousness indicating apparatus of claim 1also including a display operatively connected to the sensor signalprocessor to display a consciousness level for the person indicated bythe output signal generated by the signal processor.
 10. Theconsciousness indicating apparatus of claim 3 also including a displayoperatively connected to the sensor signal processor to display aconsciousness level for the person indicated by the output signalgenerated by the signal processor.
 11. The consciousness indicatingapparatus of claim 5 also including a display operatively connected tothe sensor signal processor to display a consciousness level for theperson indicated by the output signal generated by the signal processor.12. The consciousness indicating apparatus of claim 6 also including asingle computing device to perform the computing for the sensorcomputing processor and the facial nerve processor.
 13. The apparatus ofclaim 3 in which the array of facial muscle sensors is also adapted togenerate sensor signals representing the simultaneous activity of afifth different facial muscle area.
 14. The apparatus of claim 4 inwhich the array of facial muscle sensors is also adapted to generatesensor signals representing the simultaneous activity of a fifthdifferent facial muscle area.
 15. The apparatus of claim 5 in which thearray of facial muscle sensors is also adapted to generate sensorsignals representing the simultaneous activity of a fifth differentfacial muscle area.
 16. The apparatus of claim 6 in which the array offacial muscle sensors is also adapted to generate sensor signalsrepresenting the simultaneous activity of a fifth different facialmuscle area.
 17. The apparatus of claim 8 in which the array of facialmuscle sensors is also adapted to generate sensor signals representingthe simultaneous activity of a fifth different facial muscle area. 18.The apparatus of claim 9 in which the array of facial muscle sensors isalso adapted to generate sensor signals representing the simultaneousactivity of a fifth different facial muscle area.
 19. The apparatus ofclaim 10 in which the array of facial muscle sensors is also adapted togenerate sensor signals representing the simultaneous activity of afifth different facial muscle area.
 20. The apparatus of claim 11 inwhich the array of facial muscle sensors is also adapted to generatesensor signals representing the simultaneous activity of a fifthdifferent facial muscle area.
 21. An apparatus for indicating theconsciousness of a person, comprising in combination: K. at least onefacial muscle sensor grouping adapted to generate a first sensor signalrepresenting the activity of a first facial muscle area that elicits afirst portion of the facial expression of the person; L. a facial musclestimulator adapted to activate a facial nerve in said first facialmuscle area; and M. a processor apparatus operatively coupled to thefacial muscle sensor grouping to (i) receive at least the first sensorsignal from the first facial muscle sensor grouping, (ii) determine aparalysis level for the facial muscle area based on the first sensorsignal received subsequent to activation of the facial nerve by thefacial muscle stimulator, and (iii) generate an output signal based onat least the first sensor signal and the determined paralysis level,whereby the output signal indicates the consciousness of the persondespite partial paralysis of the nerve-activated first facial musclearea.
 22. The consciousness indicating apparatus of claim 21 wherein thefacial muscle stimulator includes a first facial muscle stimulatorproviding a first carrier signal at a first predetermined frequency tothe facial muscle area, and a second facial muscle stimulator providinga second carrier signal at a second predetermined frequency to the firstfacial muscle area, whereby the first and second facial musclestimulators cooperatively stimulate a facial nerve in the first facialmuscle area at a third stimulation frequency comprising the differencebetween the first and second predetermined frequencies.
 23. Theconsciousness indicating apparatus of claim 22 wherein the first andsecond facial stimulators each also comprise a facial muscle sensor. 24.The consciousness indicating apparatus of claims 23 includes (i) atleast a second facial muscle sensor grouping including the second facialmuscle stimulator, said second grouping being adapted to generate asecond sensor signal representing the activity of a second facial musclearea that elicits a second portion of the facial expression of theperson, and (ii) the processor apparatus is operatively connected to thesecond facial muscle sensor grouping to also receive the second sensorsignal and utilize the second sensor signal to generate the outputsignal.
 25. The consciousness indicating apparatus of claim 24 whereineach facial muscle sensor grouping includes a surface electromyogramadapted to be physically attached the person's on face in positionallowing the monitoring of a facial muscle.
 26. The consciousnessindicating apparatus claim 25 also having an artifact filter forfiltering the sensor signals received by the processor apparatus toremove an artifact representing muscle activity caused by known stimulusto the person not indicative of the person's consciousness, whereby theoutput signal generated by the processor indicates the consciousness ofthe person with reduced distortion from such artifact.
 27. Theconsciousness indicating apparatus of claim 26 wherein the artifactfilter includes an artifact detector connected to an external deviceadapted to interact with the person, said detector providing a detectionsignal to the artifact filter upon activation of the external device tointeract with the person.
 28. The consciousness indicating apparatus ofclaim 21 also including a display operatively connected to the sensorsignal processor to display a consciousness level for the personindicated by the output signal generated by the signal processor. 29.The consciousness indicating apparatus of claim 22 also including adisplay operatively connected to the sensor signal processor to displaya consciousness level for the person indicated by the output signalgenerated by the signal processor.
 30. The consciousness indicatingapparatus of claim 24 also including a display operatively connected tothe sensor signal processor to display a consciousness level for theperson indicated by the output signal generated by the signal processor.31. The consciousness indicating apparatus of claim 25 also including adisplay operatively connected to the sensor signal processor to displaya consciousness level for the person indicated by the output signalgenerated by the signal processor.
 32. The consciousness indicatingapparatus of claim 26 also including a display operatively connected tothe sensor signal processor to display a consciousness level for theperson indicated by the output signal generated by the signal processor.33. The consciousness indicating apparatus of claim 27 also including adisplay operatively connected to the sensor signal processor to displaya consciousness level for the person indicated by the output signalgenerated by the signal processor.
 34. The consciousness indicatingapparatus of claim 21 also including second, third, fourth, and fifthfacial muscle sensor groupings adapted to respectively generate second,third, forth, and fifth sensor signals from distinct facial muscle areason the person, and wherein the processor apparatus is operativelycoupled to each such facial muscle sensor grouping to also receive, andto generate the output signal based also on, the second, third, fourth,and fifth sensor signals.
 35. The consciousness indicating apparatus ofclaim 22 also including second, third, fourth, and fifth facial musclesensor groupings adapted to respectively generate second, third, forth,and fifth sensor signals from distinct facial muscle areas on theperson, and wherein the processor apparatus is operatively coupled toeach such facial muscle sensor grouping to also receive, and to generatethe output signal also on, the second, third, fourth, and fifth sensorsignals.
 36. The consciousness indicating apparatus of claim 23 alsoincluding second, third, fourth, and fifth facial muscle sensorgroupings adapted to respectively generate second, third, forth, andfifth sensor signals from distinct facial muscle areas on the person,and wherein the processor apparatus is operatively coupled to each suchfacial muscle sensor grouping to also receive, and to base the outputsignal also on, the second, third, fourth, and fifth sensor signals. 37.The consciousness indicating apparatus of claim 24 also including third,fourth, and fifth facial muscle sensor groupings adapted to respectivelygenerate third, forth, and fifth sensor signals from distinct facialmuscle areas on the person, and wherein the processor apparatus isoperatively coupled to each such facial muscle sensor grouping to alsoreceive, and to generate the output signal based also on, the third,fourth, and fifth sensor signals.
 38. The consciousness indicatingapparatus of claim 25 also including third, fourth, and fifth facialmuscle sensor groupings adapted to respectively generate third, forth,and fifth sensor signals from distinct facial muscle areas on theperson, and wherein the processor apparatus is operatively coupled toeach such facial muscle sensor grouping to also receive, and to generatethe output signal based also on, the third, fourth, and fifth sensorsignals.
 39. The consciousness indicating apparatus of claim 26 alsoincluding third, fourth, and fifth facial muscle sensor groupingsadapted to respectively generate third, forth, and fifth sensor signalsfrom distinct facial muscle areas on the person, and wherein theprocessor apparatus is operatively coupled to each such facial musclesensor grouping to also receive, and to generate the output signal basedalso on, the third, fourth, and fifth sensor signals.
 40. Theconsciousness indicating apparatus of claim 27 also including third,fourth, and fifth facial muscle sensor groupings adapted to respectivelygenerate third, forth, and fifth sensor signals from distinct facialmuscle areas on the person, and wherein the processor apparatus isoperatively coupled to each such facial muscle sensor grouping to alsoreceive, and to generate the output signal based also on, the third,fourth, and fifth sensor signals.
 41. The consciousness indicatingapparatus of claim 28 also including second, third, fourth, and fifthfacial muscle sensor groupings adapted to respectively generate second,third, forth, and fifth sensor signals from distinct facial muscle areason the person, and wherein the processor apparatus is operativelycoupled to each such facial muscle sensor grouping to also receive, andto generate the output signal based also on, the second, third, fourth,and fifth sensor signals.
 42. The consciousness indicating apparatus ofclaim 33 also including third, fourth, and fifth facial muscle sensorgroupings adapted to respectively generate third, forth, and fifthsensor signals from distinct facial muscle areas on the person, andwherein the processor apparatus is operatively coupled to each suchfacial muscle sensor grouping to also receive, and to generate theoutput signal based also on, the third, fourth, and fifth sensorsignals.
 43. The consciousness indicating apparatus of claim 1 whereinthe sensor signal processor generates at least a patterned portion ofthe output signal based on relative differences among the sensor signalsand thereby the different activities of the different facial muscleareas represented by the sensor signals.
 44. The consciousnessindicating apparatus of claim 43 wherein the sensor signal processoralso generates at least a summed portion of the output signal based onthe summation of the sensor signals and thereby the different activitiesof the different facial muscle areas represented by the sensor signals.45. The consciousness indicating apparatus of claim 2 wherein the sensorsignal processor generates at least a patterned portion of the outputsignal based on relative differences among the sensor signals andthereby the different activities of the different facial muscle areasrepresented by the sensor signals.
 46. The consciousness indicatingapparatus of claim 45 wherein the sensor signal processor also generatesat least a summed portion of the output signal based on the summation ofthe sensor signals and thereby the different activities of the differentfacial muscle areas represented by the sensor signals.
 47. Theconsciousness indicating apparatus of claim 3 wherein the sensor signalprocessor generates at least a portion of the output signal based onrelative differences among the sensor signals and thereby the differentactivities of the different facial muscle areas represented by thesensor signals.
 48. The consciousness indicating apparatus of claim 47wherein the sensor signal processor also generates at least a summedportion of the output signal based on the summation of the sensorsignals and thereby the different activities of the different facialmuscle areas represented by the sensor signals.
 49. The consciousnessindicating apparatus of claim 4 wherein the sensor signal processorgenerates at least a portion of the output signal based on relativedifferences among the sensor signals and thereby the differentactivities of the different facial muscle areas represented by thesensor signals.
 50. The consciousness indicating apparatus of claim 49wherein the sensor signal processor also generates at least a summedportion of the output signal based on the summation of the sensorsignals and thereby the different activities of the different facialmuscle areas represented by the sensor signals.
 51. The consciousnessindicating apparatus of claim 5 wherein the sensor signal processorgenerates at least a portion of the output signal based on relativedifferences among the sensor signals and thereby the differentactivities of the different facial muscle areas represented by thesensor signals.
 52. The consciousness indicating apparatus of claim 51wherein the sensor signal processor also generates at least a summedportion of the output signal based on the summation of the sensorsignals and thereby the different activities of the different facialmuscle areas represented by the sensor signals.
 53. The consciousnessindicating apparatus of claim 6 wherein the sensor signal processorgenerates at least a portion of the output signal based on relativedifferences among the sensor signals and thereby the differentactivities of the different facial muscle areas represented by thesensor signals.
 54. The consciousness indicating apparatus of claim 53wherein the sensor signal processor also generates at least a summedportion of the output signal based on the summation of the sensorsignals and thereby the different activities of the different facialmuscle areas represented by the sensor signals.
 55. The consciousnessindicating apparatus of claim 7 wherein the sensor signal processorgenerates at least a portion of the output signal based on relativedifferences among the sensor signals and thereby the differentactivities of the different facial muscle areas represented by thesensor signals.
 56. The consciousness indicating apparatus of claim 55wherein the sensor signal processor also generates at least a summedportion of the output signal based on the summation of the sensorsignals and thereby the different activities of the different facialmuscle areas represented by the sensor signals.
 57. The consciousnessindicating apparatus of claim 8 wherein the sensor signal processorgenerates at least a portion of the output signal based on relativedifferences among the sensor signals and thereby the differentactivities of the different facial muscle areas represented by thesensor signals.
 58. The consciousness indicating apparatus of claim 57wherein the sensor signal processor also generates at least a summedportion of the output signal based on the summation of the sensorsignals and thereby the different activities of the different facialmuscle areas represented by the sensor signals.
 59. The consciousnessindicating apparatus of claim 13 wherein the sensor signal processorgenerates at least a portion of the output signal based on relativedifferences among the sensor signals and thereby the differentactivities of the different facial muscle areas represented by thesensor signals.
 60. The consciousness indicating apparatus of claim 59wherein the sensor signal processor also generates at least a summedportion of the output signal based on the summation of the sensorsignals and thereby the different activities of the different facialmuscle areas represented by the sensor signals.
 61. The consciousnessindicating apparatus of claim 20 wherein the sensor signal processorgenerates at least a portion of the output signal based on relativedifferences among the sensor signals and thereby the differentactivities of the different facial muscle areas represented by thesensor signals.
 62. The consciousness indicating apparatus of claim 61wherein the sensor signal processor also generates at least a summedportion of the output signal based on the summation of the sensorsignals and thereby the different activities of the different facialmuscle areas represented by the sensor signals.
 63. The consciousnessindicating apparatus of claim 24 wherein the sensor signal processorgenerates at least a portion of the output signal based on relativedifferences among the sensor signals and thereby the differentactivities of the different facial muscle areas represented by thesensor signals.
 64. The consciousness indicating apparatus of claim 63wherein the sensor signal processor also generates at least a summedportion of the output signal based on the summation of the sensorsignals and thereby the different activities of the different facialmuscle areas represented by the sensor signals.
 65. The consciousnessindicating apparatus of claim 25 wherein the sensor signal processorgenerates at least a portion of the output signal based on relativedifferences among the sensor signals and thereby the differentactivities of the different facial muscle areas represented by thesensor signals.
 66. The consciousness indicating apparatus of claim 65wherein the sensor signal processor also generates at least a summedportion of the output signal based on the summation of the sensorsignals and thereby the different activities of the different facialmuscle areas represented by the sensor signals.
 67. The consciousnessindicating apparatus of claim 31 wherein the sensor signal processorgenerates at least a portion of the output signal based on relativedifferences among the sensor signals and thereby the differentactivities of the different facial muscle areas represented by thesensor signals.
 68. The consciousness indicating apparatus of claim 67wherein the sensor signal processor also generates at least a summedportion of the output signal based on the summation of the sensorsignals and thereby the different activities of the different facialmuscle areas represented by the sensor signals.
 69. The consciousnessindicating apparatus of claim 34 wherein the sensor signal processorgenerates at least a portion of the output signal based on relativedifferences among the sensor signals and thereby the differentactivities of the different facial muscle areas represented by thesensor signals.
 70. The consciousness indicating apparatus of claim 69wherein the sensor signal processor also generates at least a summedportion of the output signal based on the summation of the sensorsignals and thereby the different activities of the different facialmuscle areas represented by the sensor signals.
 71. The consciousnessindicating apparatus of claim 35 wherein the sensor signal processorgenerates at least a portion of the output signal based on relativedifferences among the sensor signals and thereby the differentactivities of the different facial muscle areas represented by thesensor signals.
 72. The consciousness indicating apparatus of claim 71wherein the sensor signal processor also generates at least a summedportion of the output signal based on the summation of the sensorsignals and thereby the different activities of the different facialmuscle areas represented by the sensor signals.
 73. The consciousnessindicating apparatus of claim 36 wherein the sensor signal processorgenerates at least a portion of the output signal based on relativedifferences among the sensor signals and thereby the differentactivities of the different facial muscle areas represented by thesensor signals.
 74. The consciousness indicating apparatus of claim 73wherein the sensor signal processor also generates at least a summedportion of the output signal based on the summation of the sensorsignals and thereby the different activities of the different facialmuscle areas represented by the sensor signals.
 75. The consciousnessindicating apparatus of claim 38 wherein the sensor signal processorgenerates at least a portion of the output signal based on relativedifferences among the sensor signals and thereby the differentactivities of the different facial muscle areas represented by thesensor signals.
 76. The consciousness indicating apparatus of claim 75wherein the sensor signal processor also generates at least a summedportion of the output signal based on the summation of the sensorsignals and thereby the different activities of the different facialmuscle areas represented by the sensor signals.
 77. The consciousnessindicating apparatus of claim 41 wherein the sensor signal processorgenerates at least a portion of the output signal based on relativedifferences among the sensor signals and thereby the differentactivities of the different facial muscle areas represented by thesensor signals.
 78. The consciousness indicating apparatus of claim 77wherein the sensor signal processor also generates at least a summedportion of the output signal based on the summation of the sensorsignals and thereby the different activities of the different facialmuscle areas represented by the sensor signals.
 79. The consciousnessindicating apparatus of claim 26 wherein said facial muscle areas areselected from among the frontalis area, the corrugator area, thezygomatic area, the masseter area, and the orbicularis oculi area. 80.The consciousness indicating apparatus of claim 34 wherein said facialmuscle areas are selected from among the frontalis area, the corrugatorarea, the zygomatic area, the masseter area, and the orbicularis oculiarea.
 81. The consciousness indicating apparatus of claim 39 whereinsaid facial muscle areas are selected from among the frontalis area, thecorrugator area, the zygomatic area, the masseter area, and theorbicularis oculi area.
 82. The consciousness indicating apparatus ofclaim 67 wherein said facial muscle areas are selected from among thefrontalis area, the corrugator area, the zygomatic area, the masseterarea, and the orbicularis oculi area.
 83. The consciousness indicatingapparatus of claim 68 wherein said facial muscle areas are selected fromamong the frontalis area, the corrugator area, the zygomatic area, themasseter area, and the orbicularis oculi area.
 84. A method ofdetermining the consciousness of a person, the method comprising thesteps of: A. mounting at least four facial muscle activity sensors sothat each activity sensor generates an activity signal based on thelevel of activity of a different facial muscle group on the person; andB. processing said activity signals to generate a first output signalbased on the summation of the activity signals for the sensed facialmuscle groups.
 85. The consciousness determining method of claim 84 alsoincluding as step (C): reporting the first output signal to a monitor inorder to provide an indicator of the consciousness the person.
 86. Theconsciousness determining method of claim 84 also including in step (B):processing said activity signals to generate a second output signalbased on the differences between the activity signals for the sensedfacial muscle groups.
 87. The consciousness determining method of claim86 also including as step (C): reporting the first and second outputsignals to a monitor in order to provide an indicator of theconsciousness the person.
 88. The consciousness determining method ofclaim 84 also including as step (C): stimulating a nerve in at least oneof the sensed facial muscle groups and determining the level ofparalysis from the muscle activity sensed by a facial muscle sensor. 89.The consciousness determining method of claim 88 also including as step(D): calibrating the first output signal based on the paralysis leveldetermined in step (C).
 90. The consciousness determining method ofclaim 88 also including as step (D): reporting to a monitor theparalysis level determined in step (C).
 91. The consciousnessdetermining method of claim 89 also including as step (E): reporting toa monitor the paralysis level determined in step (C) and the firstoutput signal as calibrated in step (D).
 92. The consciousnessdetermining method of claim 89 in step (B): processing said activitysignals to generate a second output signal based on the differencesbetween the activity signals for the sensed facial muscle groups. 93.The consciousness determining method of claim 90 also including in step(B): processing said activity signals to generate a second output signalbased on the differences between the activity signals for the sensedfacial muscle groups.
 94. The consciousness determining method of claim91 also including in step (B): processing said activity signals togenerate a second output signal based on the differences between theactivity signals for the sensed facial muscle groups; and including instep (E) also reporting the second output signal to the monitor in orderto provide an indicator of the consciousness the person.
 95. Theconsciousness determining method of claim 92 also including as step (E):reporting the first and second output signals and paralysis level to amonitor in order to provide an indicator of the consciousness theperson.
 96. The consciousness determining method of claim 93 alsoincluding as step (E): reporting the first and second output signals toa monitor in order to provide an indicator of the consciousness theperson.
 97. The consciousness determining method of claim 84 alsoincluding in step B: filtering the activity signals to remove from thefirst output signal an artifact representing muscle activity caused bystimulus to the person not indicative of the person's consciousness. 98.The consciousness determining method of claim 85 also including in stepB: filtering the activity signals to remove from the first output signalan artifact representing muscle activity caused by stimulus to theperson not indicative of the person's consciousness.
 99. Theconsciousness determining method of claim 86 also including in step B:filtering the activity signals to remove from the at least one outputsignal an artifact representing muscle activity caused by stimulus tothe person not indicative of the person's consciousness.
 100. Theconsciousness determining method of claim 87 also including in step B:filtering the activity signals to remove from at least one output signalan artifact representing muscle activity caused by stimulus to theperson not indicative of the person's consciousness.
 101. Theconsciousness determining method of claim 91 also including in step B:filtering the activity signals to remove from the first output signal anartifact representing muscle activity caused by stimulus to the personnot indicative of the person's consciousness.
 102. The consciousnessdetermining method of claim 94 also including in step B: filtering theactivity signals to remove from at least one output signal an artifactrepresenting muscle activity caused by stimulus to the person notindicative of the person's consciousness.
 103. The consciousnessdetermining method of claim 96 also including in step B: filtering theactivity signals to remove from at least one output signal an artifactrepresenting muscle activity caused by stimulus to the person notindicative of the person's consciousness.
 104. The consciousnessdetermining method of claim 84 wherein, in step A, the four facialmuscle areas are selected from among the frontalis area, the corrugatorarea, the zygomatic area, the masseter area, and the orbicularis oculiarea.
 105. The consciousness determining method of claim 87 wherein, instep A, the four facial muscle areas are selected from among thefrontalis area, the corrugator area, the zygomatic area, the masseterarea, and the orbicularis oculi area.
 106. The consciousness determiningmethod of claim 89 wherein, in step A, the four facial muscle areas areselected from among the frontalis area, the corrugator area, thezygomatic area, the masseter area, and the orbicularis oculi area. 107.The consciousness determining method of claim 97 wherein, in step A, thefour facial muscle areas are selected from among the frontalis area, thecorrugator area, the zygomatic area, the masseter area, and theorbicularis oculi area.
 108. The consciousness determining method ofclaim 99 wherein, in step A, the four facial muscle areas are selectedfrom among the frontalis area, the corrugator area, the zygomatic area,the masseter area, and the orbicularis oculi area.
 109. Theconsciousness determining method of claim 101 wherein, in step A, thefour facial muscle areas are selected from among the frontalis area, thecorrugator area, the zygomatic area, the masseter area, and theorbicularis oculi area.
 110. The consciousness determining method ofclaim 103 wherein, in step A, the four facial muscle areas are selectedfrom among the frontalis area, the corrugator area, the zygomatic area,the masseter area, and the orbicularis oculi area.
 111. Theconsciousness determining method of claim 84 wherein, in step A, fivefacial muscle activity sensors are mounted, respectively, on thefollowing five muscle areas: the frontalis area, the corrugator area,the zygomatic area, the masseter area, and the orbicularis oculi area.112. The consciousness determining method of claim 87 wherein, in stepA, five facial muscle activity sensors are mounted, respectively, on thefollowing five muscle areas: the frontalis area, the corrugator area,the zygomatic area, the masseter area, and the orbicularis oculi area.113. The consciousness determining method of claim 89 wherein, in stepA, five facial muscle activity sensors are mounted, respectively, on thefollowing five muscle areas: the frontalis area, the corrugator area,the zygomatic area, the masseter area, and the orbicularis oculi area.114. The consciousness determining method of claim 97 wherein, in stepA, five facial muscle activity sensors are mounted, respectively, on thefollowing five muscle areas: the frontalis area, the corrugator area,the zygomatic area, the masseter area, and the orbicularis oculi area.115. The consciousness determining method of claim 99 wherein, in stepA, five facial muscle activity sensors are mounted, respectively, on thefollowing five muscle areas: the frontalis area, the corrugator area,the zygomatic area, the masseter area, and the orbicularis oculi area.116. The consciousness determining method of claim 101 wherein, in stepA, five facial muscle activity sensors are mounted, respectively, on thefollowing five muscle areas: the frontalis area, the corrugator area,the zygomatic area, the masseter area, and the orbicularis oculi area.117. The consciousness determining method of claim 103 wherein, in stepA, five facial muscle activity sensors are mounted, respectively, on thefollowing five muscle areas: the frontalis area, the corrugator area,the zygomatic area, the masseter area, and the orbicularis oculi area.118. An electrode assembly for an awareness level monitor, comprising incombination: A. a flexible layer; B. a plurality of electrodes orientedin fixed positions and integrally formed with said flexible layer; C.plural electrical connecting paths disposed on said flexible layerextending from said plural electrodes to an input of the awareness levelmonitor, with each said electrode having its own said path; saidelectrodes being located in at least four sensor clusters of fixedarrays to respectively sense muscle activity of separate facial muscleareas pre-selected from among the frontalis area, the corrugator area,the zygomatic area, the masseter area, and the orbicularis oculi area.119. The assembly of claim 118 wherein said electrodes also having astimulator cluster to stimulate a nerve in at least one of said separatefacial muscle areas.
 120. An electrode assembly for an awareness levelmonitor, comprising in combination: A. a flexible layer; B. a pluralityof electrodes oriented in fixed positions and integrally formed withsaid flexible layer; C. plural electrical connecting paths disposed onsaid flexible layer extending from said plural electrodes to an input ofthe awareness level monitor, with each said electrode having its ownsaid path; said electrodes being located in at least (i) two sensorclusters of fixed arrays to respectively sense muscle activity ofseparate facial muscle areas pre-selected from among the frontalis area,the corrugator area, the zygomatic area, the masseter area, and theorbicularis oculi area; and (ii) a stimulator cluster to stimulate anerve in at least one of said separate facial muscle areas.
 121. Theassembly of claim 119 wherein said electrodes also include a groundelectrode providing a grounding path for the sensing clusters.
 122. Theassembly of claim 120 wherein said electrodes also include a groundelectrode providing a grounding path for the sensing clusters andstimulating cluster.
 123. The assembly of claim 118 including anartifact filtration device for removing anomalous surgically inducedartifacts, said filtration device being coupled between said electricalconnecting paths and said input of the awareness level monitor.
 124. Theassembly of claim 120 including an artifact filtration device forremoving anomalous surgically induced artifacts, said filtration devicebeing coupled between said electrical connecting paths and said input ofthe awareness level monitor.
 125. The assembly of claim 122 including anartifact filtration device for removing anomalous surgically inducedartifacts, said filtration device being coupled between said electricalconnecting paths and said input of the awareness level monitor.
 126. Theassembly of claim 125 wherein said flexible layer is linearlynon-extensible along said electrical paths to thwart breaks inconductivity along said paths.
 127. The assembly of claim 126 includingan adhesive coating on said flexible layer overlaying said electricalpaths but free from said electrodes.
 128. The assembly of claim 127including conductive coating overlaying said electrodes.
 129. A methodfor maintaining an appropriate level of patient awareness underanesthesia, the steps including: A. providing at least one electrodeassembly comprising: a flexible layer; a pattern of electricallyconductive material, disposed upon one side of said flexible layerwherein said pattern contains at least two electrodes and is adapted tobe connected to a signal receiving means; a non-conducting adhesive thatelectrically isolates at least one electrode from another electrode, butallows at least two electrodes to contact the tissue of said patient; B.attaching said assembly to the face of said patient; C. picking up asignal with the electrodes; D. receiving the signal in a processingdevice through a signal receiving means; E. processing the signalreceived from the electrodes to determine what facial expression thesignal represents by comparing the signals from different electrodes,the signals being reflective of the patient's facial muscle tonus; F.displaying the processed signal for viewing by an anesthesiologist on adisplay; G. anesthetizing the patient with an initial dosage ofanesthetic to create muscle relaxation in a desired level of awareness;and H. controlling the patient's level of awareness.
 130. The awarenesslevel method of claim 129 wherein said processing step includesdetecting and filtering out artifacts unrepresentative of the patient'sexpression through the steps of: i. detecting when an artifactgenerating device is in operation; ii. quantifying the artifactgenerating device's effect on the signal as picked up by the facialmuscle sensors; and iii. subtracting from the signal the portion causedby the artifact; whereby the artifact has a reduced effect on thesignal.
 131. The awareness level method of claim 129 including, aftersaid attaching step, stimulating a nerve in the patient's face with anelectrode.
 132. The awareness level maintenance method of claim 129wherein said providing step includes: i. providing a non-extensiblematerial characterized by resisting linear distortion; ii. applyingthrough the mask means an electrically conductive material in patternadapted to contact at appropriate sensing points the skin over at leastone facial muscle group and to connect said electrically conductivematerial over said sensing points to a signal receiving means; iii.coating with a non-conducting adhesive said non-extensible materialexcept at areas that correlate with said electrodes contactingappropriate sensing points of said face; iv. sealing the electrodeassembly with a detachable cover layer opposite said flexible layer; v.separating electrode assemblies from each other if said non-extensiblematerial has more than one electrode assembly prepared upon saidnon-extensible material; and said attaching step includes detaching saidcover layer before attaching said assembly to said face of said patient.133. The awareness level maintenance method of claim 132 wherein saidnon-conducting adhesive is applied through a second mask means adaptedto prevent adhesive from covering said electrodes at points correlatingto said sensing points.
 134. The awareness level maintenance method ofclaim 132 wherein said non-conducting adhesive is coated on saidnon-extensible material after releasable dots are placed over saidelectrically conductive material at points corresponding to said sensingpoints.
 135. The awareness level maintenance method of claim 132 whereinsaid non-conducting adhesive is applied as a preshaped pad adapted tocover the electrically conductive material except at points correlatingto said sensing points.
 136. The awareness level method of claim 132including, after said attaching step, stimulating a facial muscle nervein the patient's face with an electrode. 1 The awareness levelmaintenance method of claim 129 wherein said electrodes define apreconfigured array adapted to contact at appropriate sensing points theskin over one or more muscle groups of said face.
 138. The awarenesslevel maintenance method of claim 131 wherein said electrodes define apreconfigured array adapted to contact at appropriate sensing points theskin over one or more muscle groups of said face.
 139. The awarenesslevel maintenance method of claim 136 wherein said muscle groups are atleast two of those among the corrogator, frontalis, zygomatic,orbicularis oculi, or masseter muscle groups.
 140. The awareness levelmaintenance method of claim 136 wherein said muscle groups are at leastfour of those among the corrogator, frontalis, zygomatic, orbicularisoculi, or masseter muscle groups.
 141. The awareness level maintenancemethod of claim 136 wherein said muscle groups are the corrogator,frontalis, zygomatic, orbicularis oculi, or masseter muscle groups. 142.The awareness level method of claim 137 including, after said attachingstep, stimulating a facial muscle nerve in at least one of said musclegroups.
 143. The awareness level method of claim 138 including, aftersaid attaching step, stimulating a facial muscle nerve in the patient'sface with an electrode.